Syringe for hypodermic injection



Jan. '19, 1965 s. J. EVERETT 3,166,070

SYRINGE FOR HYPODERMIC INJECTION Filed Dec. 5, 1961 I 13v Vin/7'01? 9/11/54 fqmrs Era/warr- United States Patent Ofi ice 3,166,070 SYRINGE FOR HYPODERMIC INJECTION Samuel James Everett, London, England, assignor to Lapis Engineering Company Limited Filed Dec; 5, 1961, Ser. No; 157,105 4 Claims. (Cl. 128-218) This invention relates to hypodermic syringes.

The nature of the invention will otherwise be clear from the appended claims when read in the light of the following description of the particular and at present preferred embodiment thereof which is illustrated in the accompanying drawings. In these drawings:

FIGURE 1 is a longitudinal section through a hypodermic syringe constructed in accordance with the invention;

FIGURE 2 is a section on the line AA of FIGURE 1 on a smaller scale;

FIGURE 3 is an outside view of the syringe on an even smaller scale;

FIGURES 4 and 5 are plan and side views of a needle 12 and bag 16 used in the syringe shown in FIGURES 1 to 3;

FIGURE 6 is an outside view of a loading assembly for inserting the needle 12 and bag 16 shown in FIGURES 4 and 5, into the syringe shown in FIGURES 1 to 3;

FIGURE 7 is an end view of the assembly shown in FIGURE 6; and

FIGURE 8 is a half sectional elevation of a modified form of plunger for use in the syringe illustrated in FIG- URES 1 to 3.

The hypodermic syringe comprises a cylindrical glass barrel or casing 10 containing an operating plunger 11 which makes sliding fluid-tight engagement with the wall of the barrel. A needle 12, consisting of a cannula 14 and a hub 15 secured about the rear end of the cannula, is removably mounted on the front end of the casing 10, and the lumen of the needle communicates with the interior of a bag 16 made of pliable sheet material. The bag and needle are located in an aperture in a bushing or gland 17 of elastomeric material which is sealed to the wall of the barrel 10, clamping means 18 being provided to deform the gland to make afiuidtight seal around the bag and the needle.

The operating plunger ll has a stem 19 of reduced diameter which extends rearwardly through a clearance hole in an end cover plate 20 removably attached to the rear end of the barrel, the stem terminating in an enlarged end portion 21. The plunger has a passage through it which is normally closed by a spring loaded ball valve 26. The open end of the passage 25 at the front end of the plunger is protected by a cap 27 screwed into the plunger, the rear face of the cap being spaced from the front face of the plunger to allow the flow of fluid from the interior of the barrel to the passage 25.

, The above mentioned gland 17 is contained by a cylindrical metal sleeve 30 mounted on the front end of the barrel 10. This sleeve houses a pair of thin-metal discs 31, 32 which are clamped against projecting annular shoulders, formed on the inside of the sleeve, by upsetting the wall of the sleeve adjacent the shoulders. Projecting forwardly from the front disc 31 is a bayonet socket 33 concentric with the disc. Located inthe space between the discs is a pair of part cylindrical metal collets 34 whose outer surfaces fit closely against the inner surface of the sleeve 30, and whose end faces are spaced a short distance from the respective discs.

The gland 17 is formedby injecting a mass of silicone rubber into the space between discs 31, 32 and this material fills the gaps between the collets 34 and the respective discs, and also fills the space between the'collets except for a cylindrical aperture 35, the discs 31, 32 being formed with correspondingly shaped apertures so as not to obstruct gland aperture 35. The, mass of silicone rubber which forms the gland 17 continues integrally into the space immediately behind the rear disc 32 so as to form a yielding end wall 36 to the casing 10. This wall is dished forwardly to leave a frusto conical space communicating at its narrowest part with the gland aperture 35.

The silicone rubber which forms the gland 17 and the end wall 36 is bonded to the glass barrel 10 and to the sleeve 30 and so that the sleeve is secured to the barrel without any direct rigid connection. l l 1 The above mentioned clamping means 18 comprise a clamping ring 40 fitting loosely over the outside of. sleeve 30. The ring has a pair of inwardly projecting pegs 41 and 42 which pass through holes in the sleeve 30 and bear against the collets 34. One peg, 42, is formed as a screw extending through a threaded hole in the clamping ring 40 and carries at its outer end a knurled finger wheel 43 facilitating rotation of the peg '42 to ,vary the inward pressure exerted on thecollets by the pegs. I p

The. bag 16 is formed by welding together two layers of thin polyethylene sheet material, and in consequence is very pliable. The bag is so dimensioned that when it is fully expanded it will fill the cross section of the barrel 10, and in its flattened condition is wider than the aperture 35 through which it is passed when first inserted into the barrel. In order to facilitate the insertion of the bag into the barrel of the syringe through gland aperture 35, it

is first positioned over the hub 15, as shown in FIGURES sheath is of stilf but springy material such as celluloid rigid P.V.C. or the like, and is of a size to pass through the gland aperture 35.

The bag is folded lengthwise to fit inside the sheath, and is resiliently gripped over the hub by the sheath which is so dimensioned that it must be expanded slightly to fit over the hub. A radially projecting pin 15A on the hub pierces the wall of the bag and extends through the slot in the sheath. This peg is adapted to be engaged in the slot of the socket 33, as will be explained below.

Preferably, suitable lubricant such as a sticking to the syringe. The'sheath and its contents may be housed in a sealed container (not shown) and the whole sterilised ready for use.

silicone oil to preventits glass barrel 10 during operation of the To load the bag and needle into the barrel, the plunger 11 is first drawn outwardly to its rearmost position and the rear .end of the sheath (the right hand end as seen in FIGURE 4), is inserted through the socket 33 and the gland aperture 35. i

The peg 15A on the needle hub 15 is guided into the axially extending part of the bayonet slot in the socket 33, and then by'rotating the sheath, into the circumferential part ofthe slot. The sheath is then drawn for-' 41 and 42 press the collets 34 inwardly to deform the gland '17 and collapse the aperture 35 about the bag gland now forming a fluid tight seal and the hub, the about the hub.

' As a preliminary to filling the syringe with medica ment or other fluid, the plunger 11 is movedinwardly in the barrel so that the bag 16 is collapsed between Patented Jan. 19, 1965 the outside of the bag is treated with a ened by unscrewing the yielding end wall 36 and the plunger ll. The bag is forced by the plunger into the frusto-conical recess defined by wall 36 and any air in the bag is expelled through the lumen of the cannula-14. The size and shape of the plunger is however such that it cannotfill the space in wall 36 and so the crushing force which can be applied to the bag is limited. This, and the yielding nature of end wall 36 prevent the bag from being torn. As the plunger moves inwardly, air contained in the space within the barrel not occupied by the bag 16 passes outwardly through the passage 25 against the action of the spring loaded ball valve 26, and in this way substantially all the air in thisspace is expelled. The

cap 27 on the front of the plunger prevents the bag fro blocking the passage 25during this process. r Y

The sharp end of the cannula -14 is'now dippedinto a supply of medicament to be injected, and the plunger to collapse it and expel the medicament through the lumen of the needle.

When the injection is completed the clamp 18 1s slack 42 thus releasing the grip the peg exerted on the bag and the needle by the gland 17. The hub is rotated and pulled forwardly out of the bayonet socket 33, bringing the bag with it. The needle and bag are either discarded or re-ssterilised for future use, and the syringe may be loaded with a fresh bag .and needle for another injection operation.

Since the arrangement is such that only the bag and needle come into contact with the medicament or with the patient, there is no need for any other part of the syringe to be sterilised after a single use.

Another feature of the syringe is, its ability to deliver accurately metered dosages, even of a few'cubic centi-.

metres. This derives from the .fact that the bag is emptied progressively from its rear end to its front end by the plunger, so that'the displacement of the plunger 7 corresponds with the amount of fluid contained in the bag. This progressive emptying would not beachieved if the space within the barrel not filled by the bag was not exhausted of air prior The syringe can of course be used for drawing off.

barrel through the gland aperture 35 and the socket 33. It is found that the bag can. be removed in this way in the bag, in

without any substantial loss of the fluid spite of the. comparatively small cross-section of the gland opening through which the bag must pass.

The syringe is described above as employing a needle in which a needle mount constituted by the'hub 15 is secured about the end of a cannula 14, this mount being clamped in the flexible gland 17. a p

Other forms of needle mount can of course be used in conjunction with the syringe. For example, a hollow needle mount whose front portion is formed as the male part ofa Luer lock coupling can be positioned 7 'in the gland-the said front portion forming a nipple to which can be coupled a Luer socket secured about the rear end'of a cannula. In this case the loading assembly to filling the bag. The pres ence'ofair in this space would also prevent the plunger from being pushed fully forward into the barrel.

illustrated in FIGURES 6 and 7 is modified by the substitution for the needle 12 of the hollow needle mount.

It will be appreciated that a flexible gland such as that described above can equally well be used in syringes in which the medicament comes into direct contact with the walls of the barrel or casing.

Variationand modifications in the construction and operation of the syringe specifically described herein will of course be possible within the scope of the appended claims. I

According to a particular modification, the passage 25, instead of emerging at the rear end of th e enlarged portion of theplunger, extends through the stem 19 and openson to the rear, face of the enlargement 21 at the rear end of the stem. The ball valve 26 is dispensed with and the passageis-closed when required by the users thumb.

, Another form of plunger which can be used with the syringe shown in FIGURES 1 to 3 is illustrated in FIG- URE 8. 'This plunger 111 has a stem 119 secured at its rear end, and its cylindrical surface is helically knurled so that the surface cannot form a fluid tight seal against 7 the wall of the barrel 10. z Ihe plunger is formed with an annular recess 112 housing a washer 120 which is of flexible material, for example, silicone rubber. The diameter of the Washer is larger than that of the barrel 10 so that when the plunger is inserted in the rear end of the barrel the periphery'of the washer engages the wall of the barrel. In operation the Washer 120 acts as a cup leather, that is: when the plunger is moved rearwardly, the washer is pressed against the front face of the recess 1'12 and forms a fluid tight seal with the wall of the barrel 10; when the plunger is moved forwardly, the a washer flexes to allow the passage of air between the periphery of the washer and thewall of the barrel.

.-I claim:

1. In a hypodermic syringe a casing having at its forward end an end wall defining an aperture for removably receiving a collapsible bag, said aperture being of reduced cross-sectional size relative to the interior of the casing, the end wall at said forward end of the casing constituting a bushing of elastic material sealed to a side Wall of the casing, a plunger extending slidably into the casing from the rear end thereof, a collapsible bag with a needle, hub for holdingfluid contents of the syringe,

said bag in'laterally collapsed condition being removably insertable through said aperture into said casing, means for sealing said bag in said aperture with the interior of the bag opening through said aperture to the exterior, of the casingsaid means comprising clamping means ,operable to deform said bushing to collapse the aperture, thereby forming a fluid-tight seal around the bag,srearward movement ofsaid plunger operating to reduce air pressure within said casing and causing said bag to fill with fluid passing through said aperture, whereby said bag is expanded to ,fill the interiorof the casing over its full cross section. l

2. A syringe in accordance-with claim 1 in which rigid clamping members are embedded in the material of the bushing so as partially to surround the said aperture,

and the clamping means are operable to press those mem bers towards each other to collapse the aperture.

3. In a hypodermic syringe including a chamber for removably receiving a collapsible bag containing a treatment fluid, a barrel wall, an apertured end wall made of flexible material fixedly sealed to one end of said barrel Wall and a movable end wall slidable in said barrel wall in fluid tight engagement therewith, said walls defining said chamber, a collapsible bag with a needle hub removably fitted into said chamber with one end extending into said aperture in sealingsengagement with the wall defining the aperture, -said movable end wall constituting the face of a plunger whereby upon movement of the plunger toward said aperltured end wall the bag is collapsed, the flexibility of said apertured end wall protect- 2,604,685 7/52 Harms 128-347 7 ing the bag against being torn. 2,677,373 5/54 Barradas 128-2116 Y 4. A syringe in accordance with claim 3 in which the 2,690,179 9/54 Fox 128-216 fixed end wall is dished forwardly to form a space into 2,950,717 8/60 Bouet 128 2'18.'1

which the bag is pressed by the plunger, the plunger face 5 a a being fiat so that it cannot fill the space, whereby the FOREIGN PATENTS extent to which the bag can be collapsed by the plunger 32,325 1/24 Denmark 1S llmfled- 622,620 12/35 Germany. 7

References Cited by the Examhyler 10 LOUIS R. PRINCE, Primary Examiner. V i V V UNITED STATES PATENTS RICHARD J. HOFFMAN, JORDAN FRANKLIN, 2,148,038 2/39 Raybould 285374 Examiners. 2,453,590 11/48 Poux 128-218.1 

1. IN A HYPODERMIC SYRINGE A CASING HAVING AT ITS FORWARD END AN END WALL DEFINING AN APERTURE FOR REMOVABLY RECEIVING A COLLAPSIBLE BAG, SAID APERTURE BEING OF REDUCED CROSS-SECTIONAL SIZE RELATIVE TO THE INERIOR OF THE CASING, THE END WALL AT SAID FORWARD END OF THE CASING CONSTITUTING A BUSHING OF ELASTIC MATERIAL SEALED TO A SIDE WALL OF THE CASING, A PLUNGER EXTENDING SLIDABLE INTO THE CASING FROM THE REAR END THEREOF, A COLLAPSIBLE BAG WITH A NEEDLE HUB FOR HOLDING FLUID CONTENTS OF THE SYRINGE, SAID BAG IN LATERALLY COLLAPSED CONDITION BEING REMOVABLY INSERTABLE THROUGH SAID APERTURE INTO SAID CASING, MEANS FOR SEALING SAID BAG IN SAID APERTURE WITH THE INTERIOR OF THE BAG OPENING THROUGH SAID APERTURE TO THE EXTERIOR OF THE CASING, SAID MEANS COMPRISING CLAMPING MEANS OPERABLE TO DEFORM SAID BUSHING TO COLLAPSE THE APERTURE, THEREBY FORMING A FLUID-TIGHT SEAL AROUND THE BAG, REARWARD MOVEMENT OF SAID PLUNGER OPERATING TO REDUCE AIR PRESSURE WITHIN SAID CASING AND CAUSING SAID BAG TO FILL WITH FLUID PASSING THROUGH SAID APARTURE, WHEREBY SAID BAG IS EXPANDED TO FILL THE INTERIOR OF THE CASING OVER ITS FULL CROSS SECTION. 